n. (pl. cacti or cactuses) any succulent plant of the family Cactaceae, with a thick fleshy stem, usu. spines but no leaves, and brilliantly coloured flowers. Phrases and idioms:
cactus dahlia any kind of dahlia with quilled petals resembling a cactus flower. Derivatives:
cactaceous adj. Etymology: L f. Gk kaktos cardoon